Early Assessment of Burn Depth with Far Infrared Time-Lapse Thermography.

Background: Diagnosing the extremes of superficial burns and full-thickness burns is straightforward. It is in the middle ground of partial-thickness burns where the diagnostic difficulties emerge; it can take up to 3 to 5 days for signs of healing to appear. We hypothesize that cooling partial-thickness burns and tracking the rate of rewarming will immediately reflect the condition of the burn: shallow partial-thickness burns that retain cell health and blood flow will rewarm rapidly, and deeper burns with damaged microvessels will rewarm slowly.

Study Design: We enrolled 16 patients with isolated, partial-thickness burns on their extremities who were diagnosed as indeterminate by our burn surgeon. Within 24 hours after presentation, room-temperature saline was poured over the burn as a cooling challenge. An infrared camera that was sensitive to body temperature produced false-color images showing pixel-by-pixel temperatures. A time-lapse recording from the infrared camera images taken as the burn rewarmed produced a time-temperature curve that reflected the kinetics of rewarming. The outcomes variable was whether or not the patient received a skin graft, which was determined 72 hours after presentation.

Results: The method correctly predicted whether or not the patient required a skin graft.

Conclusions: Here we report a new technique that permits determination of wound viability much earlier than clinical examination. Due to the simplicity of the method, non-experts can successfully perform the technique on the first day of the burn and make the correct diagnosis and decision to graft or not to graft.